US2626727A

US2626727A - Material receiving, storing, and dispensing apparatus

Info

Publication number: US2626727A
Application number: US48166A
Authority: US
Inventors: William J Gibbs; Carl H Larsen
Original assignee: AMF Inc
Current assignee: AMF Inc
Priority date: 1948-09-08
Filing date: 1948-09-08
Publication date: 1953-01-27
Anticipated expiration: 1970-01-27

Description

27, 1953 w. J. GIBBS EI'AL 2,626,727

MATERIAL RECEIVING, STORING, AND' DISPENSING APPARATUS Filed Sept. 8, 1948 3 Sheets-Sheet l Fis.|

INVENTOR WILLIAM J. GIBBS CARL H. LARSEN BL- 4 4m ATTORNEY 3 w. J. GIBBS ETAL MATERIAL RECEIVING, STORING, AND DISPENSING APPARATUS 5 Sheets-Sheet 2 Filed Sept. 8, 1948 mdl NdE

ATTORNEY Jan. 27, 1953 w. J. GIBBS ETAL 2,626,727

MATERIAL RECEIVING, STORING, AND DISPENSING APPARATUS Filed Sept. 8, 1948 5 Sheets-Sheet 3 INVENTOR WILLIAM J. GIBBS B CARL H. LAR SEN Jam ATTORNEY Patented Jan. 27, 1953 MATERIAL RECEIVING, STORING, AND DISPENSING APPARATUS William J. Gibbs and Carl H. Larsen, Brooklyn, N. Y., assignors to American Machine & Foundry Company, a corporation of New Jersey Application September 8, 1948, Serial No. 48,166

21 Claims. 1

This invention relates to improvements in material receiving, storing and dispensing apparatus of the self -leveling type.

In apparatus of this general type such as shown in copending patent application S. N. 736,479 filed March 22, 1947, by Christopher Bockius it is desired that the upper surface of the material stored in such a dispenser be always maintained at a constant predetermined level regardless of whether material is added to or removed from the dispensing unit. Sometimes when material is stored in bulk friction between the material and the inner shell which surrounds the path of travel of the material carrying platform is sufficient to interfere with the calibrated springs raising or lowering the material stored the distance required to maintain the top thereof at a constant predetermined level. As a result the top of the material will either be at too high or too low a level in the dispenser.

Originally this problem was provided for in this type of dispenser by a mechanical device which would positively raise the top of the material to the desired level if the counter-balancing mecha nism failed to raise same to the proper level. If the top of the material was at too high a level pressure would be exerted on the material itself to lower the carrier platform to the extent desired. In other words mechanical force was applied each time to position the load correctly.

It is an object of this invention to solve this problem by providing compensating means which when set will provide for a gradual increase or diminishment of the amount of force exerted by the counterbalancing means as needed so that as the frictional element begins to affect the uniform movement of the carrier, an appropriate adjustment in the amount of force exerted by the counterbalancing means is also made.

Another object is to provide calibrated counterbalancing spring mechanism which will exert a calibrated counterbalancing force on the material supporting carrier of a self-leveling dispenser which will be greater when the carrier travels in an upward direction than when the carrier travels in a downward direction to compensate for friction and thereby maintain the top of the material at a constant level regardless of whether material is added to or removed from the dispenser.

Another object is to provide a self-leveling apparatus wherein the force exerted by the caliloaded to facilitate unloading and to overcome friction encountered when the material is raised upwardly.

Another object is to mount the springs in a self leveling dispenser so as to stagger the time said springs become active over the distance traveled by said carrier to compensate for friction encountered when the carrier moves downwardly and thereby maintain the top of the material at a constant predetermined level.

A further object is to provide a simple device for readily changing the capacity of a self-leveling storing and dispensing apparatus to handle material of one weight and size at one time and another material of different weight and size at another time.

Another object is to provide a device for changing the capacity of a self-leveling storing and dispensing apparatus that can be readily operated regardless of whether material to be stored has or has not been placed in the dispenser.

Other objects and features of the invention will appear as the description of the particular physical embodiment selected to illustrate the invention progresses. In the accompanying drawings, which form a part of this specification, like characters of reference have been applied to corresponding parts throughout the several views which made up the drawings.

Fig. 1 is a sectional end elevation of the storing and dispensing apparatus.

Fig. 2 is a sectional side elevation taken on the line 2-2 of Figure 1, illustrating the hydraulic booster.

Fig. 3 is a partial front elevation showing the partially extended springs connected by graduated links to the frame of the dispenser.

Fig. 4 is a schematic view of a modified form of the invention showing how the invention may be used to readily change the capacity of a self -leveling storing and dispensing apparatus.

The housing for the self-leveling dispenser used to illustrate this invention is similar to that shown in copending patent application of Christopher Bockius, S. N. 736,479, referred to above.

Referring to Figs. 1, 2 and 3 of the drawings the dispenser is provided with a bottom plate It having a drain plug l2. Affixed to the bottom plate H) are suitable casters [4 which permit the dispenser to be readily moved about the floor. The sides l8 of the bottom plate iii are bent upwardly to form an enclosed liquidtight drain pan for collecting any liquids which may drip from the articles being carried by the materia1 handling apparatus.

At the front end of the dispenser in each corner,

3 are upright angle irons l6 (Fig. 2) which are secured at the bottom by suitable means such as welding to the upwardly bent sides [8 of the bottom plate I0. Secured to the upper ends of the upright angleirons l6 are suitable cross bars 26 which constitute the skeleton framework for the dispenser.

The dispenser has a cover plate 22 which covers the top of the apparatus except for an opening formed in the center portion thereof through which the carrier platform 24 raises and lowers material. The vertical path of travel of the carrier platform 24 is closely surrounded by a rec tangular inner shell 26 which late'rall'y supports material carried and supported by the carrier platform 24.

The inner shell 26 is secured at its lower end to the bottom plate and at its upper end to the cover plate 22. The innershell 26 has projections 28 which extend above the cover plate 22 to laterally support material elevated above the surface of the cover plate 22, Two sides of the upwardly extending projections 28 have a hinged mounting 39 which permits the sides to be lowered into a horizontal position. The hinged projections are held in vertical position by suitable means such as hooks 32 carried by the projecting plates 28. V p 7 The carrier platform 24 is raised and lowered, by means of calibrated counterbalancing springs, a distance correlated with the weight of each increment or decrement added to or removed from the material supported on the platform to maintain the top of the material at a constant predetermined level with respect to the top of the dispenser. While various types of calibrated springs can be employed to practice the teachings of this invention, for purposes of illustration calibrated tension springs have been used to illustrate the invention in this application. By the term calibrated springs is meant a spring which deflects at a uniform rate within its rated capacity.

The carrier platform 24 is supported on four bolts 34 secured by suitable means such aswelding to each corner of the carrier platform 24. A bracket 36 is adjustably connected to each bolt 34 and extends through slits 38 formed in each corner of the rectangular inner shell 26. One end 4| of each of the

sprocket chains

40, 42, 44 and '46 are "connected to each bracket 36 and supports the carrier platform 24 for vertical movement within the inner shell 28.

Elongated flexible members such as

sprocket chains

40, 42, 44 and 46 travel over suitable pulleys such as sprockets 48 and under the sprockets 50 and are connected at their opposite ends to suitable anchor bolts 52.

Sprocket chains

40 and 46 travel over another pair of sprockets, mounted on the skeleton frame 26 adjacent the far end of the carrier platform 24 (shown in copending application of Christopher Bockius referred to above). I

A loop is formed in the

sprocket chains

40, 42, 44 and 46 between the sprockets 48 and the anchor bolts 52. Supported by this loop are sprockets 50 mounted at opposite ends of a double saddle shaft consisting of bars 54and 56. Calibrated tension springs 53 are hooked at one end at spaced intervals to the

saddle shaft bars

54 and 56.

In the embodiment used to illustrate the invention some of the calibrated tension springs 58 are connected directly to the bottom plate It by suitable anchors 60 while others are connected by suitable means such, for example, as graduated

links

62, 64, and 66 to the anchors 60 to stagger the time said springs become active when the carrier 24 is lowered by material placed thereon. Some of the springs 58 also are connected to the CI'OSs frame 68 of a suitable mechanical spring stretcher. In the present application for purposes of illustration the spring stretcher shown consists of a cylinder E6 attached at one end to the cover plate 22 of the dispensing apparatus. It will be understood that other suitable stretching mechanisms could also be used for this purpose. The number of calibrated springs having staggered connections and the number of calibrated springs connected to the spring stretching mechanism may be varied as necessary to handle the material for which the dispenser is used.

A hydraulically operated piston 12 is reciprocally mounted within the cylinder 'Hland has at its actuating end the cross frame as. The piston 12 is pushed downwardly by means of a suitable hydraulic fluid which is pumped by a conventional pump, such as a hydraulic bumper jack, actuated by the pump handle l4. The fluid pumped by the pump handle '54 is released when desired by a suitable valve 76. By actuating the pump rod 74 when the valve 16 is closed pressure will be built up behind the piston '12 which causes the pistonto stretch the springs which are connected to the frame 63. When the valve 76 is opened the fluid is allowed to escape which allows the piston 12 to be freely moved in and out of the cylinder 79 by the calibrated tension springs connected to the frame 63.

A suitable removable door 18 is mounted at the frontend of the dispenser to permit access to be had to the springs and operating mechanism described. For additional details concerning the construction of a self leveling, storing and dispensing apparatus for bulk material, reference may be made to 'copending application of Christopher Bockius, S. N. 736,479, mentioned hereinbefore.

The operation of the invention may be briefly described s follows:

When material to be stored, such as machine parts undergoing manufacture, are placed on top of the carrier platform 24, the weight of the parts causes the platform to descend a distance correlated with the weight added to the platform. As more parts are added, the carrier platform 24 descends still further so that the top of the 'material 'supported on the carrier platform 24 is always maintained at a constant predetermined level. The plate 28 laterally supports that portion of the material which extends above the upper surface 22 of the dispensing apparatus.

When the carrier platform 24 is depressed by material placed thereon it pulls downwardly on the ends 4| of

sprocket chains

46, 42, 44 and 46 which are connected to the supports 36. This causes the sprocket chains just mentioned to rotate the sprockets 48 thereby shortening the loop in which the sprockets 50 are supported. Since all the sprockets 48 are keyed on the shaft 49 the

sprocket chains

40, 42, 44 and 46 all move an equal distance in the same direction thereby preventing the carrier platform 24 from tilting.

As the sprocket chain loops are shortened the

saddle shafts

54 and 56 are elevated thereby causing the spring 58 which are connected directly to the anchors 60 to be stretched. As additional material is added the springs 58, which are attached to the shortest graduated link 62, become active. As the loading process continues,

additional springs connected to the graduated

links

64 and 66 progressively become active also as shown in Fig. 3.

It Will be understood that the valve I6 is open when the dispenser is being loaded so that as the

saddle shafts

54 and 56 travel upwardly the springs attached to the upport 68 causes the piston I2 to be moved upwardly inside of the cylinder I0. During the loading process friction between the material supported on the carrier platform 24 and the inner shell 26 gradually increases. Therefore the force exerted on the

saddle shafts

54 and 56 will vary not only in accordance with the weight of the material supported on the carrier platform 24 but also in accordance with the amount of friction between the material and the inner shell 26 of the dis penser. To compensate for this variation the graduated link structure consisting of

links

62, 64 and 66 shown in Fig. 3 is employed to stagger the time the counterbalancing spring tension force become-active as the

saddle shafts

54 and 56 move upwardly.

As a result when the frictional element begins to modify the downward force exerted by the weight of the material on the platform 24, allowance for this retarding effect has already been made by staggering the time the springs 50 become active in supporting the material. Consequently the top of the material being stored is maintained at a constant predetermined level since the friction and the force of the calibrated springs have been balanced to lower the material the distance desired.

After the dispenser is fully loaded and the operator commences to remove the article from the dispenser it has been found that the amount of friction existing between the material and the inner shell is greater than the amount of friction. which exists when the dispenser is being loaded. Therefore as the operator removes material from the dispenser, the top of the material, because of friction, is prevented from rising to the predetermined level at which it is desired to have the material maintained. When this occurs the operator manipulates the pump handle I4 and applies pressure in the cylinder I0 on the end of the piston I2. This causes the piston I2 to be moved downwardly thereby stretching the springs attached at one end to the support 68 as shown in Fig. 3 in dotted outline. This causes additional spring tension force to be exerted on the

saddle shafts

54 and 56. When the required amount of force has been added to counteract the increased friction encountered when the carrier travels upwardly the carrier 24 automatically raises the top of the material to the level desired and maintains it there. Thus the material reassumes the desired predetermined level with respect to the top 22 of the dispensing apparatus.

The invention also has considerable value as a device for varying the capacity of a self-leveling storing and dispensing apparatus which is used to store stacked material rather than material in bulk as will now be explained.

By closing the valve 16, when the dispenser is empty, the piston 12 will be locked in its lowermost position. As a consequence the capacity of the dispenser will be increased by the rating of the springs attached to the piston I2. By leaving the valve I6 open, the springs attached to the piston 12 will not be stretched when the apparatus is loaded. Accordingly the capacity 0f the apparatus will be less by the amount of springs rendered inactive in this manner. V

In cases where a still greater amount of capacity changing is desired in a self-leveling storing and dispensing apparatus a plurality of spring locking devices shown in Fig. 4 may be employed for activating and deactivating the calibrated tension springs. In such a case a single control knob I30 such as shown may be employed so that the task of changing the capacity of the apparatus can be easily and quickly accomplished by an operator. In Fig. 4 the

cylinders

80, 82 and 84 have hydraulically actuated

pistons

86, 88 and 90 similar to those designated by the numerals I0 and 12 in Fig. 1 and are employed for locking the lower end of as many calibrated ten sion springs against movement as is necessary to counterbalance the weight of the material to be stored in the dispenser.

The

cylinders

80, 82 and 84 are connected by

ducts

92, 94 and 96 to ports 98, I00 and I02 respectively formed in the valve cylinder I04. When the pump handle I38 is moved up and down, a conventional pump IIO pumps suitable hydraulic fluid received from the reservoir tank I06 through duct I I2, port I I4 into the valve cylinder I94 between the collars I22 and I24. Hydraulic fluid is permitted to fiow freely between the far end of the cylinder I04 to the tank reservoir I06 through port H6 and duct H8. The path of flow of the hydraulic fluid is controlled by the position of the valve piston I20 in the cylinder I04. Valve piston I20 may be manually moved along the length of cylinder I04 by means of the knob I30. A scale I36 having notches I34 into which the pointer I32 slips indicates the position of the valve piston in the cylinder I04. When the pointer I32 is set in the notch I35 corresponding to the weight of the material to be handled before loading the dispenser, hydraulic fluid is locked in the cylinders which have pistons connected to springs which are to be active when the dispensing apparatus is loaded.

If an operator should inadvertently over estimate the weight of the material to be handled and sets the pointer I32 at the 400 pound notch, for example, instead of at the 300 pound notch the error may be simply corrected even after the apparatus is partially loaded by merely moving the pointer I32 to the correct notch. When this is done hydraulic fluid is allowed to escape through port I02 thus permitting the piston 90 to be pulled up into the cylinder 84 by the springs connected thereto and thus deactivating the springs which are not needed to counterbalance the load.

On the other hand if the operator inadvertently under estimates the weight of the material and sets the pointer I32 at 200 pounds when it should have been set at 400 pounds the operator will notice that as material is placed on the dispenser the top of the material descends to a level lower than desired. To correct this error the operator merely has to put the pointer I32 over to the 400 pound notch and then operate the pump IIO by means of the pump handle I38. This causes the additional springs required to counterbalance the load to be stretched by means Of the

pistons

88 and 90 being forced downwardly by hydraulic fluid being pumped into the

cylinders

82 and 84. It will thus be seen that a simple one knob control has been provided in accordance with the object of this invention which permits an operator to readily adjust the capacity of the dispensing apparatus regardless of whether material has or has not been loaded into the dispensing apparatus.

Heretofore it was the practice to connect and disconnect springs manually from the anchors at the bottom of the dispensing apparatus. If the incorrect number of springs was chosen to counterbalance the load and this error was not noticed until after the dispenser was partially loaded it would be for all practical purposes impossible to correct this error without unloading the dispenser because the springs would be under tension and they would have to be stretched manually to either hook or u'nhook them. As previously mentioned errors in fixing the capacity of the dispenser can be corrected at anytime by merely moving the pointer I32 to the correct desig'nation. If it should so happen that the operator has under estimated the load to be handled, the pump handle I38 is given a few strokes to stretch the additional springs required to counterbalance the material.

While we have shown only three

cylinders

80, 82 and S4 in the modified form of our invention, it should be understood that this number has been chosen for purposes Of illustration only and that a greater or lesser number of cylinders could be used so as to obtain whatever amount of variability is desired. It should also be understood that one or more springs can be connected at their lower ends to each of the

pistons

86, 88 and 90 in the manner shown in Fig. 1. Likewise for purposes of simplicity and clarity we have not shown springs in Fig. 4 since the manner in which they may be connected is clearly shown in Figs. 1, 2' and 3. stood that as a practicable matter, a certain number of springs are always needed to take care of the minimum requirement in counterbalancing the usual run of material in a self-levelin apparatus. at all times between the saddle shafts 54 and58 and the bottom'of the dispenser ID as shown by the spring connected to anchor 60 in Figs. 1 and 3.

When the pointer I32 is set on zero position none of the springs connected to the

pistons

86, 88 and fili w-ill be stretched. If desired the zero position could have a designation corresponding to the spring force-exerted by the springs which remain connected at all times between the saddle shaft and the dispensing apparatus. Similarly if the pointer I32 is positioned opposite to num ber 2210 the pistons 83 and Gil-will not be locked against movement and when the

saddle shaft

54 and 56 travels upwardly as shown in Fig. 3' the

pistons

38 and 98 will be drawn upwardly inside of the

cylinders

82 and 84 by the springs which are connected to the

pistons

88 and 99. When the

pistons

88 and 90 travel upwardly they push the hydraulic fluid through

ducts

94 and 96 out through ports I60 and I02 into port I I6 and duct I I8 back into the reservoir tank I06. When the saddleshafts 54 and 56 are lowered the springs connected to the

pistons

88 and 99 allow the

pistons

88 and 90 to descend. This causes hydraulic fluid to flow from the tank I06 through duct H8, portIIB, ports I and I92,

ducts

94 and 96 into the

cylinders

82 and 84.

When the pistons '88 and 96 are in their'lowermost position and the pointer I32 is set at some figure higher than the zero position one or more of the ports 98, I00 and I02 will be confinedbetween the collars I22 and I24 so that hydraulic fluid cannot escape therethrough. In other words the apparatus'disclosed in Fig. 4 constitutes a convenient method for varying the ca- It will be further under- Such springs would be connected 8. essa of a self-leveling storing and dispensing apparatus by activating and deactivating calibrated springs by the simple movement of a control knob.

It should be understood that while hydraulic means have been employed for the purpose of illustrating how the lower end of calibrated tension springs may be locked in place by only mov ing a single control knob, other suitable mechanical means could also be employed for looking the lower end of the calibrated tension springs against movement by use of a single control knob and thatthe scope of this application should nottherefore be restrictedto the use of hydraulic apparatus for accomplishing this objective. V k 7 U y W The invention above described may be varied in construction within the scope of the claims, for the particular device selected to illustrate the invention is but one of many possible embodiments of the same. The invention, therefore, is not to be restricted to the precise details of the structure shown and described.

What is claimed is:

1. In a self-leveling dispensing apparatus, a material carrying platform, elongated flexible members supporting said material carrying platform for up and down movement, an inner shell surrounding the path of travel of said platform, guide members for confining said elongated members to a predetermined path of travel, counterbalancing calibrated tension springs connected to said elongated flexible members for raising and lowering said carrier a distance corresponding with the weight of each increment or decrement added to or removed from the carrying platform, anchorages for said springs, and lost motion connections between said springs and said anchorages, said lost motion connections being constructed and arranged to provide varying amounts of lost motion to stagger the time said springs become effective in accordance with the amount of friction encountered at the'various positions of the descending material carrying platform.

2. In a self-leveling dispensing apparatus, a material supporting platform, elongated'fiexible members supporting said platform for vertical movement, rotary members over which said elongated flexible members are' trained, an inner shell surrounding the path of travel of said platform to laterally confine material supported thereon, calibrated tension springs connected to said elongated flexible members for counterbalancing the weight of material supported on said platform, and graduated link mechanism controlling the time said springs commence stretching with respect to the distance traveled by said platform to compensate for frictional differences en countered when the carrier descends.

3. Apparatus of the self-leveling type for receiving, storing and dispensingmaterial wherein the top of the material stored is maintained at a constant predetermined level' comprising, an outer housing enclosing said dispensing apparatus, a material supporting platform mounted for vertical movement within said outer housing, an inner shell closely surrounding the vertical path of movement of said platform to laterally support material carried thereon, counterbalancing calibrated springs coasting with said platform to raise and lower said "carrier a distance corresponding to each increment and decrement of material added to and removed from the'material supported on said platform tomaintain the top of the material at aconstant predetermined level,

normally inactive calibrated spring means for supplementing the counterbalancing force exerted by said first named calibrated springs and mechanism for stretching said calibrated spring means after said dispenser has been loaded to add additional counterbalancing force to that exerted by said first named springs to overcome friction retarding the upward movement of said carrier.

4. Apparatus of the self-leveling type for receiving, storing and dispensing material wherein the top of the material stored is maintained at a constant predetermined level comprising, an outer housing enclosing said dispensing apparatus, a material supporting carrier mounted for vertical movement within said outer housing, an inner shell closely surrounding the vertical path of movement of said carrier to laterally support material carried thereon, elongated flexible members connected at one end to said carrier for supporting said carrier for vertical movement, anchors connecting the other end of said elongated flexible members to a stationary part of said dispensing apparatus, a saddle shaft supported in loops formed in said elongated flexible members intermediate the ends of said elongated flexible members, calibrated tension springs connected at one end to said saddle shaft, spring anchors connecting the other end of at least one of said springs to a stationary part of said dispensing apparatus, and a spring stretching device associated with the remainder of said springs to apply when required additional counterbalancing force to said saddle shaft by stretching the remainder of said springs to counterbalance material supported on said carrier.

5. A storing and dispensing apparatus of the self-leveling type for storing material in bulk comprising, a framework for the dispensing apparatus, a material supporting platform mounted for vertical movement within said framework, an inner shell surrounding the vertical path of movement of said platform for laterally confining material carried by said platform, a set of calibrated counterbalancing springs for lowering said platform a distance correlated with the weight of each increment of material added to the material supported on said platform, additional calibrated springs for supplementing the counterbalancing force exerted by said first named set of calibrated springs when material is removed from said platform to compensate for friction between the inner shell and the material supported on said platform, and means for stretching said additional calibrated springs an amount sumcient'to maintain the top of the material at a constant predetermined level.

6. Apparatus of the self-leveling type for receiving, storing and dispensing material in bulk,

comprising, a frame, a vertically'movable material supporting platform associated with said frame, confining walls surrounding the vertical path oftra'vel of said materialsupporting platform, a plurality of active and inactive calibrated springs for counterbalancing material on said supporting platform, means interconnecting said platform with said springs, mechanism for staggering the time said active springs become energized in counterbalancing material carried on said platform to provide a uniform descent of said platform, and mechanism for stretching said inactive calibrated springs when said dispenser is loaded to facilitate a uniform ascent of the material on said platform.

'7. Apparatus of the self leveling type for receiving, storing and dispensing material comprising, a housing, a material carrier mounted for up and down movement with respectf to said housing, calibrated springs for raising and lowering said carrier a distance correlated with the weight of material supported on said carrier to maintain the top of the material at a substantially constant level, elongated flexible members interconnecting said springs with said carrier, and a hydraulically operated piston connected to one end of at least one of said springs to render the same inactive when the carrier descends and for rendering said spring active by stretching said spring which the carrier is to ascend.

8. Apparatus of the self-leveling type for receiving, storing and dispensing material comprising, a housing, a material carrier mounted for up and down movementwith respect to said housing, calibrated counterbalancing springs for counterbalancing material supported on said carrier to maintain the top of the material at a substantially constant uniform level, and lost motion connections connected to one end of said calibrated springs to stagger the time said springs become energized in counterbalancing material placed on said carrier.

9. Apparatus as specified in claim 8 in combination with a spring stretcher employed for stretching additional calibrated springs after the apparatus is loaded to supplement the amount of force applied to the carrier to maintain the top of the material at a substantially constant level when the apparatus is being unloaded.

10. Apparatus ofthe self-leveling type for receiving, storing and dispensing material comprising, a housing, a material carrier mounted for up and down movement with respect to said housing, elongated flexible members for supporting said carrier for up and down movement within said housing, calibrated tension springs connected with said elongated flexible members to exert a force thereon in a direction opposite to the direction of movement of said flexible members and in an amount correlated with the distance said flexible members move, and mechanism for varying the amount of force exerted by said springs on said elongated flexible members when the dispenser is being loaded and unloaded to maintain the top of the material at a substantially constant level at all times.

11. Apparatus of the self-leveling type for receiving, storing and dispensing material wherein the top of the material stored is maintained at a constant predetermined level comprising, a housing for said apparatus, a material carrier mounted for up and down movement within said housing,- elongated flexible members supporting atone end said carrier, pulleys mounted at the top of said housing over which said elongated flexible members travel, mechanism for causing said elongatedflexible members to move equally in the samedirection, means for connecting the other end of" said elongated flexible members to said housing and forming a loop in said members between said means and said pulleys, a spring support carried in said loop, calibrated tension springs connected at one end to said spring support to assist in counterbalancing material placed on said carrier, and a staggering device connecting the other end ofsaid springs to said housing to stagger the time said springs begin to exert force in counterbalancing the carrier.

12. Apparatus of the-self-leveling type for receiving, storing and dispensing material wherein the top of the stored material is maintained at a constant predetermined level regardless of whether material is added to or removed from the dispenser, comprising a housing for said apparatus, a material carrier adapted and arranged to move up and down within said housing, pulleys connected to said carrier adjacent the upper end of the path of travel of said carrier, elongated flexible members connected at one end to said carrier and passing over said pulleys to support said carrier for up and down movement, calibrated tension springs connected at one end with said elongated flexible members for applying calibrated tension thereto and means secured to and traveling with the other end of said tension springs and mechanism locking said means from movement to cause the springs to stretch when said carrier is depressed to obtain the amount of tension required to counterbalance the material placed on said carrier.

13. In a self-leveling storing and dispensing apparatus, a frame, a material supporting platform movable up and down with respect to said frame, calibrated tension springs for counterbalancing material placed on said platform to raise and lower the material supported thereon a distance corresponding to each decrement and increment removed from and added to the material on said platform so as to maintain the top of the material at a constant level, means interconnecting one end of each of said springs with the platform to cause said ends of said springs to travel a distance proportional to that traveled by the platform, movable means traveling with the other end of said springs, mechanism for rendering as many of said movable means as desired stationary when the apparatus is empty and a manually operated control knob for setting said mechanism to activate the number of calibrated tension springs necessary to counterbalance material to be handled in the apparatus.

14. A self-leveling storing and dispensing apparatus, comprising a housing, a material supporting member mounted for movement up and down with respect to said housing, calibrated counterbalancing springs connected at one end with said member for raising and lowering said member at a uniform rate corresponding to the weight of the material supported thereon so as to maintain the top of the material at a constant predetermined level, and a movable control for locking against movement the other end of as many of said springs as necessary to counterbalance the type of material to be handled in said apparatus.

15. A self-leveling material storing and dispensing apparatus comprising, a housing, a carrier movable up and down with respect to said housing, calibrated tension springs for counterbalancing material placed on said carrier to raise and lower the material supported thereon a distance corresponding to each decrement and increment removed from and added to the material placed on said platform so as to maintain the top of said material at a constant predetermined level, elongated flexible members supporting said carrier for up and down movement, calibrated tension springs associated at one end with said elongated flexible members, means connecting the other end of at least one of said calibrated tension springs to said housing, a capacity changing control knob readily reached from the outside of said housing for changing the capacity of said apparatus, and devices actuated by said knob for connecting optional numbers of springs by moving said knob a distance corresponding 12 to a scale showing the weight of material to be counterbalanced in the apparatus.

16. A self-leveling apparatu for storing and dispensing material comprising, a housing, a material carrier movable up and down with respect to said housing, calibrated tension springs for counterbalancing material placed on said carrier to raise and lower the material supported on said carrier a distance corresponding to each decrement and increment of material removed from and added. to the material supported on said carrier so as to maintain the top of the material at a constant predetermined level, elongated flexible members connected to said carrier for supporting the carrier and material supported thereon, calibrated tension springs associated at one end with said elongated flexible members, a spring holder connected to and traveling with the other end of said calibrated tension springs, and mechanism for stretching as many of said springs as is needed to counterbalance the material on said carrier by moving the holders of said springs to a predetermined position with respect to said housing.

1'7. A self-leveling storing and dispensing apparatus, comprising a housing, a carrier mounted for vertical movement within said housing, calibrated tension springs connected to said carrier for counterbalancing material supported thereon, movable anchors connected to the other end of said calibrated tension springs, hydraulic cylinders and pistons for exerting pressure on said movable anchors to move them to a predetermined position With respect to said housing to stretch the calibrated tension springs after the dispenser is partially loaded to exert additional counterbalancing force thereon, a pump for pumping hydraulic fluid into said cylinders, and a control valve for fixing the number of cylinders into which hydraulic fluid is pumped to stretch the tension springs attached to the anchors so moved by hydraulic fluid.

8. A device for changing the capacity of a self-leveling storing and dispensing apparatus, comprising a material carrier for supporting material to be stored, calibrated springs connected to said carrier for counterbalancing material supported thereon, mechanism allowing at least one of said springs to remain unstretched when said apparatus is in use, and hydraulic means for stretching at least one of said springs to change the capacity of said self-leveling dispenser.

19. Operating mechanism for a self-leveling storing and dispensing apparatus, comprising a carrier for supporting material to be stored and dispensed, calibrated tension springs for counterbalancing material supported on said carrier for raising and lowering said material a distance corresponding to each decr m n an increment added to and removed from the dispensing apparatus to maintain the top of the material at a constant predetermined level, and mechanism for staggering the time said springs become stretched in supporting material placed on said carrier and for exerting additional stretching force on said springs after the apparatus is completely loaded to apply additional counterbalancing force to the carrier.

20. The method of maintaining at a substan tially constant level the top of material stored in a bulk storing and dispensing apparatus of the self leveling type employing calibrated counterbalancing springs which comprises staggering the time the calibrated counterbalancing springs begin to stretch when the dispensing apparatus is being loaded to allow for friction retarding the material from descending in the apparatus when being loaded, and then stretching the counterbalancing springs in the self leveling apparatus a greater distance when the carrier ascends than when the carrier descends to apply additional counterbalancing force on said carrier to overcome friction retarding the upward movement of the material so as to maintain the top of the material at a constant level at all times.

21. The method of maintaining at a substantially constant level the top of the material stored in a bulk storing and dispensing apparatus of the self-leveling type having side walls surounding the material and calibrated springs for counterbalancing the material supported in the dispensing apparatus which comprises changing the amount of the counterbalancing force exerted on the carrier when it descends and increasing the amount of counterbalancing force when the material stored in bulk is being removed from the 14 apparatus so as to maintain the top of the bulk material at a substantially constant level with respect to the top of the dispensing apparatus at all times.

WILLIAM J. GIBBS. CARL H. LARSEN.

REFERENGES CITED The following references are of record in the 10 file of this patent:

UNITED STATES PATENTS